The present invention relates to a disc cartridge, and more particularly to a disc cartridge having a hard disc, especially a double-sided type housed in a casing.
In general, a disc-type data recording carrier such as a compact disc (CD), a video disc (LD) or the like is used in a manner by being removed from a packing case and then set in a recording and/or reproducing equipment such as a disc player.
Conventionally, it has been highly desirable to protect such a disc-type recording carrier from the environment because it is not only easily covered with dust or the like and damaged, but adversely affected due to variation in temperature. For this purpose, a disc cartridge has been proposed which is adapted to house or receive a disc in an envelope such as a tray, a case, or the like, to accomplish protection of the disc. Such an envelope is constructed so that a shutter for actuating a window through which a disc driving element of a disc player such as a disc head is inserted into the envelope, is opened when a disc is to be operated and closed during nonuse of the disc cartridge.
However, in the conventional disc cartridge, a disc receiver operatively connected to an actuator or shutter lock member for releasably locking the shutter, is suddenly actuated due to vibration or the like during non-use, causing the disc to be released from the disc receiver and resulting in the disc being damaged. Also, when any unexpected shock is applied to the envelope due to dropping or the like during non-use of the disc cartridge, the shutter is often suddenly opened, so that functioning of the envelope deteriorates to a degree sufficient to cause it to become unserviceable.
More particularly, when the disc cartridge is unexpectedly subject to shock during non-use due to dropping or the like, the weight of the disc overcomes a bearing capacity of the disc receiver to actuate the disc receiver which then actuates the actuator or shutter lock member and leads to releasing of the shutter from the shutter lock member so that the window is opened, causing dust and the like to readily enter into the disc cartridge therethrough. Unfortunately, the conventional disc cartridge lacks an effective manner of eliminating such a problem except by manual closing of the shutter. However, the manual closing renders handling of the disc cartridge highly troublesome, and deteriorates quality of the disc cartridge leading to failure in reliability of the disc cartridge.
Accordingly, it would be highly desirable to develop a disc cartridge which is capable of positively preventing releasing of a disc from a disc receiver and opening of a shutter due to vibration, shock, or the like unexpectedly applied to the disc cartridge during non-use of the disc cartridge, as well as keeping the disc in a state of floating in a casing to prevent contact of a recording surface of the disc with an inner surface of the casing during the non-use, so that satisfactory and reliable operation of the disc cartridge may be assured for a long period of time.